Energy transfer system for refrigerator/freezer components

ABSTRACT

An energy,, transfer system is provided for a household or commercial refrigeration appliance. The energy transfer system includes a fluid passage disposed in the housing of the appliance for enabling the transfer of a fluid into, through, and out of the housing. The fluid is circulated through a heat exchanger which can be disposed outside of a home or commercial building or underground so that the fluid is cooled by the outside air or by the ground. The cooling fluid is also utilized to cool the compressor of an air conditioning unit. A heat exchanger is also utilized for transferring heat from the cooling fluid to an interior of a building.

BACKGROUND OF THE INVENTION

[0001] This is a continuation in part of U.S. patent application Ser.No. 09/126,143, filed Jul. 30, 1998 which is a division of U.S. patentapplication Ser. No. 08/927,232, filed Sep. 10, 1997, now U.S. Pat. No.5,816,063 issued Oct. 6, 1998, which is a continuation-in-part of priorU.S. application Ser. No. 08/761,329 filed Dec. 10, 1996, now U.S. Pat.No. 5,666,817 issued Sep. 16, 1997.

FIELD OF THE INVENTION

[0002] The present invention relates to domestic and/or commercialrefrigerators and freezers. More particularly, the present inventionrelates to a system and method for utilizing cool outdoor ambienttemperature levels to reduce the energy required to operate a domesticand/or commercial refrigerator or freezer system.

BACKGROUND AND SUMMARY OF THE INVENTION

[0003] Virtually every home and apartment in this country has at leastone refrigerator for storing perishable food products. Additionally,many households also have a freezer for storing food products overextended periods of time. As a consequence of such widespread usage,these domestic appliances consume a substantial part of the electricalenergy which is generated by the nation's utility companies. In thisregard, it should be noted that despite recent strides, refrigeratorsare still only half as efficient as the theoretical limit allowed by itsuse of the Reverse Carnot Cycle. Consequently, opportunity still existsto substantially increase the energy efficiency of domesticrefrigeration appliances. Since even the newest refrigerators consumeapproximately 700 kwh of electricity per year, it should be understoodthat a substantial need still exists to increase the energy efficiencyof domestic refrigeration appliances.

[0004] In addition, the cost of operating commercial refrigerationsystems constitutes a substantial portion of the overhead expenses ofthe perishable food distribution industry. A reduction of the operatingcosts would likely translate into increased profit margins as well as areduction in consumer prices.

[0005] Accordingly, it is a principle objective of the present inventionto provide a system and method which reduces the energy required tooperate domestic and/or commercial refrigerator and freezer systems.

[0006] It is also known in the air conditioning industry that an airconditioning system can operate more efficiently if the compressor ofthe air conditioning system is appropriately cooled.

[0007] Thus, it is a further object of the present invention to providea system and method of cooling the compressor of an air conditioningsystem.

[0008] The cost of heating a grocery store during the winter months canalso be very substantial. The use of open refrigeration cabinets withinthe store greatly increases the amount of heating that is required inorder to keep shoppers comfortable. Typically, there is a large amountof heat that is generated by the refrigeration components such as thecompressor and condenser. This heat is typically vented out of thebuilding. Accordingly, it is an object of the present invention toutilize the heat generated by the refrigeration components to aid inheating a building.

[0009] These and other objects of the present invention are obtained byproviding a refrigeration system including a housing defining a coolingstorage compartment. Refrigeration means are provided for cooling thecooling storage compartment. The refrigeration means includes acompressor and a condenser. A cooling passage is provided for carryingcooling fluid for cooling at least one component of the refrigerationmeans. A storage vessel is disposed external of the housing forcontaining the cooling fluid. The cooling passage is connected to thestorage vessel. Pumping means are provided for moving the cooling fluidthrough the fluid passage in order to cool the at least one component ofthe refrigeration means. A heat exchanger is disposed in the coolingpassage, and a fan is provided for blowing air at said heat exchangerfor transferring heat from said cooling fluid to an interior of abuilding.

[0010] Further areas of applicability of the present invention willbecome apparent from the detailed description provided hereinafter. Itshould be understood however that the detailed description- and specificexamples, while indicating preferred embodiments of the invention, areintended for purposes of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

[0012]FIG. 1 is a schematic view of a household refrigeration appliancein accordance with a first embodiment of the present invention;

[0013]FIG. 2 is a perspective view of the refrigerator shown in FIG. 1,illustrating the fluid passages disposed in the side walls and top ofthe refrigerator housing;

[0014]FIG. 3 is a cross-sectional view of an insulated rollbond panelaccording to the principles of the present invention;

[0015]FIG. 4 is a perspective view of the refrigerator shown in FIG. 1,illustrating the serpentine fluid passages along with the condenserpassages disposed in the rear wall of the refrigerator or freezeraccording to the present invention;

[0016]FIG. 5 is a perspective view of the refrigerator shown in FIG. 1,illustrating the fluid passages disposed in the bottom portion of therefrigerator for cooling the compressor;

[0017]FIG. 6 is a cross-sectional view taken along line 6-6 of FIG. 4;

[0018]FIG. 7 is a perspective view of a household refrigerationappliance in accordance with the present invention wherein serpentinetubes are disposed in the walls of the housing;

[0019]FIG. 8 is a cross-sectional view of a wall of the refrigerationappliance shown in FIG. 7;

[0020]FIG. 9 is a schematic view illustrating alternative methods forcooling the condenser and for cooling the oil in the compressor;

[0021]FIG. 10 is a perspective view of a refrigerator illustratingcooling fluid passages disposed on the outer surface of the doors of therefrigerator;

[0022]FIG. 11 is a perspective view of the flexible fluid passagesconnecting the cooling fluid passages in the doors to the main housingof the refrigerator unit;

[0023]FIG. 12 is a perspective view of an open unit-type commercialrefrigeration system having cooling fluid passages disposed in the wallsthereof;

[0024]FIG. 13 is a perspective view of an open unit-type commercialrefrigeration system having cooling fluid passages disposed in theshelves thereof;

[0025]FIG. 14 is a schematic view of a commercial refrigeration systemhaving a compressor and a condenser disposed separate from itsrefrigerated enclosure unit with the compressor, condenser and unitenclosure each being cooled via cooling fluid passages which circulatefluid received from a naturally cooled heat exchanger;

[0026]FIG. 15 is a schematic view of another embodiment of the presentinvention including a fist fluid passage disposed within the housing forproviding cooling of the refrigerator housing and a second fluid passagedisposed adjacent to the food liner for cooling the food storagecompartment using a heat exchanger disposed underground;

[0027]FIG. 16 illustrates a refrigerator cabinet fabricated by injectionmolding with grooves molded into the inner surface for the passage ofheat exchange fluid;

[0028]FIG. 17 is a cross-sectional view of the cabinet wall formedaccording to the process illustrated by FIG. 16, with the food linerfoamed in place;

[0029]FIG. 18 illustrates a typical temperature profile across aconventional insulated refrigerator wall;

[0030]FIG. 19 illustrates a typical temperature profile across aninsulated refrigerator wall having fluid passages positioned near theouter wall;

[0031]FIG. 20 illustrates a typical temperature profile across aninsulated refrigerator wall having fluid passages positioned near theinner wall;

[0032]FIG. 21 is a schematic view of a commercial refrigeration systemhaving a compressor and a condenser disposed separate from itsrefrigerated enclosure unit with the compressor, condenser, and unitenclosure being cooled via cooling fluid passages and the heated coolingfluid being used to augment the heating for a building; and

[0033]FIG. 22 is a schematic view of a refrigeration system having acompressor and a condenser unit which are cooled via cooling fluidpassages which circulate fluid received from a naturally cooled heatexchanger, the warmed fluid is then used for heating the evaporator in aheating system used to heat a building.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Referring to FIG. 1, a schematic view of a householdrefrigeration appliance 10 in accordance with the present invention isshown. More specifically, the household refrigeration appliance 10depicted in FIG. 1 is a domestic refrigerator which includes an energytransfer system 12 in accordance with the present invention. It shouldbe appreciated that household refrigeration appliances, such asself-contained refrigerators and freezers, that are specifically adaptedfor use in a residential environment. In this regard, it should beunderstood that a completely different set of constraints and designcriteria may be employed with commercial refrigeration equipment, whichmay have a compressor and compressor systems remotely located from therefrigerated cabinets, enclosures and the like.

[0035] As shown in FIG. 1, the refrigerator 10 generally includes atleast one door 14 across its front to enable access to cooling storagecompartments 16. In FIG. 1, two cooling storage compartments 16 and twodoors 14 are shown.

[0036] Refrigerator 10 includes a housing 18 which surrounds the coolingstorage compartments 16. Insulating material 20 is provided around eachof the cooling storage compartments 16. According to a preferredembodiment of the present invention, a plurality of rollbond panels 22a-22 e are disposed in the rear wall, side walls, upper wall, and lowerwall of the housing 18. The rollbond panels 22 a, 22 b provided in theside walls of the housing 18 as well as the rollbond panel 22 c providedin the upper wall of housing 18, include a serpentine passage 23 whichconnects a first inlet 24 to a first outlet 26.

[0037] As shown in FIG. 3, the rollbond panels 22 a-22 c include aformed plate 28 attached to a generally flat plate 30. The formed plate28 is preferably a heat conducting metal such as aluminum. Formed plate28 includes a plurality of connecting portions 32 which are bonded togenerally flat plate 30. Formed plate 28 also includes a plurality ofpassage defining portions 34 which define the fluid passages 23 whichare preferably defined in a serpentine fashion as shown in FIG. 2. Theformed plate members 28 are bonded to the generally flat plate 30 atcontact portions 32 by welding, adhesives, or other known bondingtechniques. The insulating material 20, such as foam, can be injectedbetween the rollbond panel and the liner 38 of the cooling storagecompartments 16.

[0038] The rollbond panels 22 a-22 c can be integrally formed and thenbent into the inverted U-shape shown in FIG. 2. Alternatively, panels 22a-22 c can be independently formed and then connected to one anotherusing sufficient seals for connection therebetween so that a continuousfluid passage 23 is provided between inlet 24 and outlet 26. Inlet 24and outlet 26 are generally tubular shaped conduits which communicatewith passages 23 and are provided with a seal 40 around an annularsurface thereof.

[0039] Inlet 24 and outlet 26 communicate with heat exchanger 46 ofenergy transfer system 12. Heat exchanger 46 can be provided withcooling fins and/or a fan in order to facilitate cooling of the fluidcirculating therein.

[0040] The rear wall of the refrigerator 10 is provided with a rollbondpanel 22 d as shown in FIG. 4. Rollbond panel 22 d includes a firstfluid passage 50 which communicates with inlet 52 and outlet 54. Inlet52 and outlet 54 communicate with heat exchanger 46 of energy transfersystem 12. A condenser passage 58 is disposed adjacent to fluid passage50. Fluid passage 50 and condenser passage 58 are each preferably formedin a serpentine fashion as shown in FIG. 4. With reference to FIG. 6,the fluid passage 50 and condenser passage 58 are defined by a formedplate member 60 which is bonded to generally flat plate member 62 byconnecting portions 64. Formed plate member 60 is preferably a heatconducting metal sheet such as aluminum and includes fluid passagedefining portions 66 and condenser forming portions 68. The inlet 52 andoutlet 54 are generally formed from conduits which are connected to theinlet and outlet ends of fluid passage 50. Annular seals 70 are providedaround the annular surface of the conduits 52, 54 to connect theconduits 52, 54 to the fluid passage 50.

[0041] With reference to FIG. 1, the refrigeration mechanism ofrefrigerator 10 includes a compressor 80 which is disposed in acompartment 82 provided in a bottom portion of the refrigerator 10.Compressor 80 is disposed adjacent to rollbond panel 22 e. Compressor 80preferably includes an oil cooling system including an oil sump 84adjacent, to rollbond panel 22 e. Energy transfer from the oil sump 84to the rollbond panel 22 e helps to cool the compressor 80. Rollbondpanel 22 e is formed similarly to the rollbond panels 22 a-22 c asillustrated in FIG. 3. Rollbond panel 22 e includes a fluid passage 86connected to an inlet 88 and outlet 90, see FIG. 5. Fluid inlet 88 andoutlet 90 are each connected to the fluid vessel 46 of energy transfersystem 12. It should be noted that each of the inlets 24, 52, and 88 areconnected to fluid passage line 92 which runs through the wall 94 of adwelling. A pump 96 is disposed in line 92 for pumping cooled fluid fromheat exchanger 46 through the passages 23 and 50 of rollbond panels 22a-22 e. Pump 96 can be provided with variable speeds for increasing ordecreasing the mass flow rate of cooling fluid through the fluidpassages for controlling the cooling of the refrigerator unit 10.Furthermore, a valve 98 can be provided in fluid line 92 for controllingthe fluid flow. As shown in FIG. 9, the condenser 100 can be disposed inthe bottom compartment 102 of the refrigerator 104. The condenser 100 isintegrally formed in a roll-bond panel 106. Roll-bond panel 106 is alsoprovided with a cooling fluid passage similarly to the roll-bond panelillustrated in FIG. 6. The roll-bond panel 106 is folded within thebottom compartment 102. A fan 108 is located in the bottom compartment102 for forced convection cooling of the condenser 100. The compressor110 is also located in the bottom compartment 102. The compressor 110 isalso provided with a roll-bond panel 112 which includes a fluid passagefor the cooling oil of the compressor 110 as well as a fluid passage forthe cooling fluid from the fluid storage vessel 46. Roll-bond panel 112is constructed similar to the roll-bond panel illustrated in FIG. 6.Each of the roll-bond panels 106 and 112 are provided with fittings forconnecting with fluid passage lines which extend to the external fluidheat exchanger 46. In addition, the condenser 100, which is integrallyformed in roll-bond panel 106, is provided with fittings for connectionwith the refrigerant lines of the refrigeration system. The roll-bondpanel 112 is also provided with fittings for attachment to compressoroil lines or an oil sump of the compressor 110.

[0042] It should also be noted that the fluid passages through thehousing of the refrigerator unit may also be defined by serpentine tubes120 disposed in a heat exchange relationship within the walls of thehousing 122 as shown in FIGS. 7 and 8. The condenser tubes 124 can beprovided with a serpentine passage disposed adjacent to be in thermalcontact with the serpentine tubes 120. In addition, the fluid passages,such as serpentine tubes 120, can be provided in the doors 14 of therefrigeration appliance 10 as shown in FIGS. 10 and 11. As shown in FIG.11, the fluid passages 120 disposed in doors 14 are provided withfittings 150 which are connected to a pair of flexible hoses 152.Flexible hoses 152 are connected to fittings 152 for connecting thefluid passages 120 disposed in the doors 14 with the fluid passages 120disposed in the refrigerator housing 122.

[0043] A thin insulating layer 126 is disposed on the outside surface ofthe refrigerator housing 122, as shown in FIG. 8. The insulating layer126 can be a plastic exterior or another insulating material such as athick coat of paint. The insulating layer helps to prevent condensationof atmospheric moisture on the cabinet surface.

[0044] As shown in FIG. 1, an appropriate sensor 130 can be provided forreducing the circulation of the cooling fluid when the temperature ofthe cabinet exterior reaches the dew point of the ambient air. This isto avoid the condensation of atmospheric moisture on the cabinetsurfaces. In this case, a controller 132 would be provided whichmonitors the humidity of the room as well as the temperature of thecabinet as detected by temperature sensor 134. When the temperature ofthe surface of the cabinet, in the ambient air, approaches the dewpoint, the controller 132 would reduce the flow rate of pump 96 or shutit off completely if necessary. Although the controller and sensor areshown separate from the refrigerator housing, it should be understoodthat these may be attached to the housing or contained in amicroprocessor assembly.

[0045] The fluid used for the energy transfer system 12 according to thepresent invention can be demineralized water, or secondary refrigerantssuch as food grade glycol or brines, as determined by suitability forthe application.

[0046] With reference to FIGS. 12-14, 21 and 22, commercial embodimentsof the present invention will be described. FIGS. 12 and 13 illustratean open-type refrigerated case commonly utilized in supermarkets formerchandising perishable foods. The open-type refrigerated cases 200 aretypically connected to a refrigeration system having a compressor andcondenser with the evaporator typically within the case. The open-typerefrigerated case 200 includes a pair of sidewalls 202, a front wall204, a rear wall 206, and can also be provided with an upper wall 208.The open-type refrigerated case 200 also includes an opening 209therein. With reference to FIG. 13, the open-type refrigerated case 200includes a plurality of shelves 210 on which food is displayed.According to the principles of the present invention, the sidewalls 202,front wall 204, rear wall 206, and upper wall 208, as well as shelves210 are provided with cooling fluid passages for enabling ingress andegress of a cooling fluid circulated through a heat exchanger disposedexternal of the housing, similarly to the heat exchanger 46 shown inFIG. 1.

[0047] In addition, a pump is provided for pumping the cooling fluidthrough the fluid passages 212 in order to aid in cooling the productstorage area in addition to cooling provided by the refrigerationsystem. The fluid passages 212 disposed in the housing of the open-typerefrigerated case 200 can be defined by serpentine tubes or by roll bondpanels as shown in FIG. 3.

[0048] With reference to FIG. 14, a further embodiment of the presentinvention is shown in conjunction with a commercial refrigerated case220. As is common in supermarket refrigeration systems, the condenser224 and compressor 226 of the refrigeration system are often timesremotely located remote from the refrigerated case 220. Typically, thisis done for efficient sales area floor space utilization as well asremotely attending to the heat generated by the condensing unit 224,226. According to the present invention, cooling fluid passages 228 areutilized to cool the walls of the refrigerated case 220 as well as tocool the condenser 224 which is located separate from the refrigeratedcase 220. In this embodiment, valve 234 is provided for regulating theflow through the cooling passages for the refrigerated case 220 and thecondenser 224. Again, the cooling fluid would be circulated through aheat exchanger 46 as discussed with reference to FIG. 1. With each ofthe embodiments described above, it should be understood that thecooling fluid in the passages aid in cooling the refrigerated case 220in addition to the cooling provided by the refrigeration system.

[0049] An additional design is shown in FIG. 21 wherein the heatedcooling fluid is used to augment the heating for a building. The coolingfluid passages 228 are provided for cooling the refrigerated case 220,condenser 224, and compressor 226 of the refrigeration system. Thecooling passages 228 also include a heat exchanger portion 264 fortransferring heat to the interior of a building. A fan 266 blows airthrough the heat exchanger portion 264 as heat from the warmed coolingfluid (such as a glycol solution or other heat transferring fluids) istransferred to the interior of the building. In this embodiment, valves262 a-262 d are provided for regulating the flow through the coolingfluid passages for cooling the refrigerated case 220, condenser 224, andthe compressor 226 of the refrigeration system. Valve 262 a regulatesthe fluid path 228 to the refrigerated case 220. Valve 262 b regulatesthe fluid path 228 to the storage 232 to bypass a portion of the flowthrough the heat exchanger portion 264 to control heating. Valve 262 cis used to regulate the fluid path 228 to the heat exchanger portion264. Valve 262 d controls the fluid path 228 to the compressor 226 ofthe refrigeration system to supply additional heat to the heat exchangerportion 264. The cooling fluid passages 228 are connected to the storage232. A pump 268 circulates the cooling fluid throughout the coolingfluid passages 228.

[0050] In typical grocery store applications, with all the refrigerationthat is required, the expense of heating the building is considerable.According to the embodiment shown in FIG. 21, the heat that is absorbedduring cooling the refrigerated case 220, condenser 224, and compressor226 of the refrigeration system can be captured and used for heating thebuilding. Thus, the power required by the heating system is reduced byutilizing heat that is extracted from the refrigeration system.

[0051]FIG. 22 discloses another embodiment wherein the heated coolingfluid is used to heat the evaporator in a heating system used to heat abuilding. FIG. 22 shows a refrigerated case 400 having a condenser 402and a compressor 404 disposed separate from the refrigerated case 400.Cooling fluid passages 406 are utilized to cool the walls of therefrigerated case 400 and condenser 402 and compressor 404 of therefrigeration system. The cooling fluid passages also include a heatexchanger portion 420 for transferring heat to the evaporator 422 of theheating system. As the warmed cooling fluid transfers heat to theheating system evaporator 422, the evaporating temperature is raised,thus reducing the power required by the heating compressor.

[0052] In this embodiment, valves 416 a-416 d are provided forregulating the flow through the cooling fluid passages for cooling therefrigerated case 400, the condenser 402, and the compressor 404 for therefrigeration system. Valve 416 a regulates the fluid path 406 to therefrigerated case 400. Valve 416 b regulates the fluid path 406 to thestorage to bypass a portion of the flow through the heat exchangerportion 420 to control heating. Valve 416 c regulates the fluid path 406to the heat exchanger portion 420. Valve 416 d regulates the fluid path406 to the compressor 404 of the refrigeration system to supplyadditional heat to the heat exchanger portion 420. The cooling fluidpassages are connected to an underground storage 408. A pump 410circulates the cooling fluid throughout the cooling fluid passages 406.

[0053] In each of the above embodiments, the heat exchanger/storagecontainer (46; 408) can be disposed outdoors or underground, or in abasement of the household. When the heat exchanger/storage container(46; 408) is disposed outdoors, the cooler temperatures of the wintermonths can be taken advantage of for transferring heat away from therefrigerator 10 and its components. However, during the warmer summermonths, it would be advantageous to locate the heat exchanger/storagecontainer (46; 408) underground where a constant temperature ofapproximately 55° F. is maintained. Year-round ground temperatures atdepths of 25 feet and lower are essentially constant and typically areat a level equal to the average annual air temperature for the region.In the contiguous United States, these average temperatures range fromabout 50° F. in the northern sector to about 65° F. in the southernsector. At shallower depths, the ground temperatures are influenced bythe seasonal air temperatures and have an annual cyclic swing. At adepth on the order of one to two feet, the ground temperatures typicallyrange from a low of about 30° F. in the winter to a high of about 70° F.in the summer in the northern tier of states. In the southern tier ofstates, the seasonal range of ground temperatures at that depth istypically 50° F. to 80° F. The ground can be effective in reducing theheat gain through the appliance cabinet walls with a ground-cooling heatexchanger during periods when the soil temperature is lower than theambient air temperature surrounding the appliance. Therefore, during thepeak of the summer, the ground cooling approach may not be as effective.But for the balance of the year, the ground temperature is well belowthe ambient temperature surrounding the cabinet and the heat gainthrough the cabinet can be reduced by the energy transfer system. Thebest performance of the energy transfer system is achieved when therollbond panels are positioned within the cabinet wall relatively closeto the outer wall. They must be positioned at an adequate depth into theinsulation to minimize the potential for condensation formation on theouter surface of the cabinet when the cool heat transfer fluid iscirculated through the rollbond panel.

[0054] For a cabinet without an energy transfer system, the temperatureprofile across the insulated wall 240 from the outer wall 242 to theinner wall 244 is linear. This is displayed in FIG. 18.

[0055] Referring to FIG. 19, a rollbond panel 250 of the energy transfersystem is positioned near the outer wall 242 and a heat transfer fluidis circulated through the passages. When the fluid temperature is lowerthan the outer wall temperature and higher than the inner walltemperature, the temperature profile across the insulation decreaseslinearly from the outer wall temperature to the rollbond paneltemperature at the location of the rollbond panel 250. From the locationof the rollbond panel 250 to the inner wall 244 of the cabinet, thetemperature decreases linearly at a lower rate per unit of insulationthickness. The heat gain into the cabinet is a direct function of therate of change of temperature per unit of insulation as indicated by theslope of the temperature profile. A higher amount of heat flows intoinsulation through the outer wall 242 of the cabinet than flows out fromthe inner wall 244 into the cabinet. The difference in these heat flowsis carried to the heat sink in the ground by the heat transfer fluidflowing through the rollbond panel 250. The closer the rollbond panel250 is located to the outer wall 242, the lower the rate of change oftemperature between the rollbond panel 250 and the inner wall 244 with aresulting reduction of heat gain through the cabinet walls.

[0056] In the northern areas the ground temperatures at a shallow depth,such as one to two feet, can drop below 45° F. and be as low as about30° F. When this occurs, the energy transfer system can reverse the heatflow and thus provide cooling to the fresh food compartment. Thisreduces or eliminates the need for compressor operation to maintainfresh food compartment temperatures. The best performance of the energytransfer system when these conditions exist is achieved when therollbond panels are positioned within the cabinet insulation relativelyclose to the inner wall.

[0057] Referring to FIG. 20, the rollbond panel 250 of the energytransfer system is located near the inner wall 244 and a heat transferfluid is circulated through the rollbond panel at a temperature lowerthan the inner wall temperature. The temperature profile across theinsulation 252 decreases linearly from the outer wall temperature to therollbond panel temperature at the location of the rollbond panel 250.From the location of the rollbond panel 250 to the inner wall of thecabinet, the temperature profile increases linearly from the rollbondheat transfer fluid temperature to inner wall temperature. For thiscase, heat flows from both the outer and the inner walls of the cabinetto the rollbond panel 250. The combination of these heat flows iscarried to the heat sink in the ground by the heat transfer fluidflowing through the rollbond panels 250. The closer the rollbond panel250 is located to the inner wall 244, the greater the rate of change oftemperature between the rollbond panel 250 and the inner wall 244 andthus the greater the rate of cooling imparted to the fresh foodcompartment.

[0058] For best performance, two sets of rollbond panels 250 a, 250 b,respectively, can be positioned within the insulation as shown in FIG.15. One of the panels 250 a would be positioned near the outer wall 242of the cabinet and the other panel 250 b would be positioned near theinner wall 244 of the cabinet. During periods when the groundtemperature exceeds the storage temperature within the compartment, theheat transfer fluid would be pumped through the panel 250 a locatedclosest to the outer wall 242 to optimize the reduction of the heat gainthrough the cabinet walls. At times when ground temperature drops belowthe storage temperature of the compartment, the heat transfer fluidwould be pumped through the panel 250 b located closest to the innerwall 244, negating any heat gain into the interior of the cabinet whilealso providing cooling to the storage volume.

[0059] With reference to FIG. 15, the heat exchanger 46 provides cooledfluid through a passage 252 which connects with a valve 254 which isselectively operable to distribute fluid between two rollbond panels 250a, 250 b which extend through the housing 256 of a refrigeration unit258. The first panel 250 a is disposed near the outer wall 242. Thesecond rollbond panel 250 b is disposed near the inner wall 244.

[0060] The valve system 254 of the present invention allows theselection between a shut-off position for operation in the conventionalrefrigeration mode when the fluid cooling system is not utilized; afirst position for supplying cooling fluid to the first rollbond panel250 a; and a second position for supplying cooling fluid to the secondrollbond panel 250 b.

[0061] Alternatively, a single position for the rollbond panels withinthe cabinet walls can be selected as shown in FIGS. 19 and 20. Theposition for the single set of panels would be based on optimizingannual energy savings utilizing seasonal information on groundtemperatures. The location for optimum year-round performance would varyby climate.

[0062] With reference to FIG. 16, a refrigerator cabinet 300 which isfabricated by injection molding the outer shell 302 of a suitableplastic material. The thickness of the shell 302 is approximately in theone-quarter to one-half inch range, presenting sufficient thermalresistance to prevent the condensation of atmospheric moisture on theexposed surfaces under the normal operating conditions. It should beunderstood that the shell thickness can vary depending upon thematerials used and other environmental conditions. As shown in FIG. 16,grooves 304 are molded into the inner surface 306 of the shell 302 forthe passage of the heat exchange fluid. Prior to the foaming of thecabinet 300, foil or a sheathing of aluminum or similar heat conductingmaterial 308 is bonded to the inner surface 306, thus forming theenclosed conduits 310 for the passage of the fluid. Foam insulationmaterial 312 is injected between the foil or sheathing 308 and the foodliner 314 as shown in FIG. 17.

[0063] The invention being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A refrigeration system, comprising: a housingdefining a cooling storage compartment; refrigeration means for coolingsaid cooling storage compartment, said refrigeration means havingcomponents including a compressor and a condenser; a cooling passage forcarrying cooling fluid for cooling at least one component of saidrefrigeration means; a storage vessel disposed external of said housingfor containing said cooling fluid, said cooling passage being connectedto said storage vessel; means for moving said cooling fluid through saidat least one fluid passage in order to cool said at least one componentof the refrigeration means; a heat exchanger disposed in said coolingpassage for transferring heat from said cooling fluid to an interior ofa building by means of a fan blowing air at said heat exchanger.
 2. Therefrigeration system according to claim 1 , wherein said storage vesselis exposed to outside air.
 3. The refrigeration system according toclaim 1 , wherein said storage vessel is disposed underground.
 4. Therefrigeration system according to claim 1 , wherein said cooling fluidis brine.
 5. The refrigeration system according to claim 1 , whereinsaid cooling fluid is a glycol solution.
 6. A refrigeration system,comprising: a housing defining a cooling storage compartment;refrigeration means for cooling said cooling storage compartment, saidrefrigeration means having components including a compressor and acondenser; a cooling passage for carrying cooling fluid for cooling atleast one component of said refrigeration means; a water source forproviding said cooling fluid to said cooling passage; means for movingsaid cooling fluid through said at least one fluid passage in order tocool said at least one component of the refrigeration means; a heatexchanger disposed in said cooling passage for transferring heat fromsaid cooling fluid to an interior of a building by means of a fanblowing air at said heat exchanger.
 7. A refrigeration system,comprising: a housing defining a cooling storage compartment;refrigeration means for cooling said cooling storage compartment, saidrefrigeration means having components including a compressor and acondenser; a cooling passage for carrying cooling fluid for cooling atleast one component of said refrigeration means; a storage vesseldisposed external of said housing for containing said cooling fluid,said cooling passage being connected to said storage vessel; means formoving said cooling fluid through said at least one fluid passage inorder to cool said at least one component of the refrigeration means; aheat exchanger disposed in said cooling passage for transferring heatfrom said cooling fluid to an interior of a building by means oftransferring heat to an evaporator in the heating system.
 8. Arefrigeration system, comprising: a housing defining a cooling storagecompartment; refrigeration means for cooling said cooling storagecompartment, said refrigeration means having components including acompressor and a condenser; a cooling passage for carrying cooling fluidfor cooling at least one component of said refrigeration means; a watersource for providing said cooling fluid to said cooling passage; meansfor moving said cooling fluid through said at least one fluid passage inorder to cool said at least one component of the refrigeration means; aheat exchanger disposed in said cooling passage for transferring heatfrom said cooling fluid to an interior of a building by means oftransferring heat to an evaporator in the heating system.